A clothes-peg-shaped binuclear trans-bis(2-aminotroponato)palladium(II) complex bearing pentamethylene spacers.

rac-Bis{µ-trans-2,2'-[pentane-1,5-diylbis(azanediyl)]ditroponato}dipalladium(II), [Pd2(C19H20N2O2)2], has been synthesized and fully characterized using single-crystal X-ray diffraction, (1)H NMR, FT-IR and mass spectroscopy. The trans coordination, vaulted structure and anti conformation have been unequivocally established from the X-ray diffraction studies. This is the first example of a bis(aminotroponato)palladium complex. In the crystalline state, the molecule has twofold symmetry and each molecular unit undergoes intermolecular offset π-stacking of the tropone rings to afford heterochiral interpenetrating dimers that are aligned in a lamellar manner with a herringbone packing motif.

P-chiral phosphine-sulfonate/palladium-catalyzed asymmetric copolymerization of vinyl acetate with carbon monoxide.

Utilization of palladium catalysts bearing a P-chiral phosphine-sulfonate ligand enabled asymmetric copolymerization of vinyl acetate with carbon monoxide. The obtained γ-polyketones have head-to-tail and isotactic polymer structures. The origin of the regio- and stereoregularities was elucidated by stoichiometric reactions of acylpalladium complexes with vinyl acetate. The present report for the first time demonstrates successful asymmetric coordination-insertion (co)polymerization of vinyl acetate.

Linker-free, silica-bound olefin-metathesis catalysts: applications in heterogeneous catalysis.

A set of heterogenized olefin-metathesis catalysts, which consisted of Ru complexes with the H(2)ITap ligand (1,3-bis(2',6'-dimethyl-4'dimethyl aminophenyl)-4,5-dihydroimidazol-2-ylidene) that had been adsorbed onto a silica support, has been prepared. These complexes showed strong binding to the solid support without the need for tethering groups on the complex or functionalized silica. The catalysts were tested in the ring-opening-ring-closing-metathesis (RO-RCM) of cyclooctene (COE) and the self-metathesis of methyl oleate under continuous-flow conditions. The best complexes showed a TON>4000, which surpasses the previously reported materials that were either based on the Grubbs-Hoveyda II complex on silica or on the classical heterogeneous Re(2)O(7)/B(2)O(3) catalyst.

The first catalytic synthesis of an acrylate from CO2 and an alkene-a rational approach.

For more than three decades the catalytic synthesis of acrylates from the cheap and abundantly available C(1) building block carbon dioxide and alkenes has been an unsolved problem in catalysis research, both in academia and industry. Herein, we describe a homogeneous catalyst based on nickel that permits the catalytic synthesis of the industrially highly relevant acrylate sodium acrylate from CO(2), ethylene, and a base, as demonstrated, at this stage, by a turnover number of greater than 10 with respect to the metal.

Acrylate formation from CO2 and ethylene: catalysis with palladium and mechanistic insight.

We report the first catalyst based on palladium for the reaction of CO2, alkene and a base to form sodium acrylate and derivatives. A mechanism similar to a previously reported Ni(0)-catalyst is proposed based on stoichiometric in situ NMR experiments, isolated intermediates and a parent palladalactone. Our palladium catalyst was applied to the coupling of CO2 with conjugated alkenes.

Vinylarene/CO copolymerization and vinylarene/polar vinyl monomer/CO terpolymerization using palladium/phosphine-sulfonate catalysts.

Palladium/phosphine-sulfonate complexes were effective for the alternating copolymerization of vinylarenes with carbon monoxide (CO). The obtained copolymers had iso-enriched microstructures with ll selectivity of up to circa 60%. The catalytic system was successfully applied to the terpolymerization of vinylarene and polar vinyl monomers with CO to produce novel terpolymers, which could not be obtained by using previously developed catalysts. NMR and DSC analyses suggested that vinylarene/CO units and polar vinyl monomer/CO units were randomly distributed in the terpolymer main chains.